I would go with the
Black Magic 165 Electric Fan, it is what I have been running for 11yrs now, though mine looks more like this one
Black Magic 150B Electric Fan, just not blue. It comes with its own built in adjustable thermostat, rated for 240HP w/AC, mounts to the radiator support not the radiator, has two sets of connectors, one for automatic operation, and one for manual. I set mine up so that it comes on w/the key and runs continuously.
Don't expect to see huge gains in performance or mileage.